LiDAR derived percent understory cover of HAFE at 2m resolution.

These data are part of a large data set describing the three-dimensional structure of vegetation in portions of four, primarily forested national parks: Prince William Forest Park, Catoctin Mountain Park, C&O Canal National Historical Park, and Harpers Ferry National Historical Park. All four parks are within the National Capital Region Inventory and Monitoring Network and contain forest monitoring plots that have been measured yearly since 2005. We acquired Light Detection and Ranging (LiDAR) surveys of these parks during leaf-on conditions in 2009 and 2010. From these data four primary products were generated: (1) digital elevation models (2-m resolution DEMs), (2) Canopy height models (at 1- and 2-m resolutions), (3) canopy gaps (defined as 2-m grid cells with canopies shorter than 3m), and (4) understory percent cover (2-m resolution). All data products are made available in standard GIS-compatible file formats and are intended to be used to understand spatial patterns in vegetation structure and as documentation of baseline conditions. Future assessments of vegetation structure using the same or similar methods would enable assessment of change in vegetation structure over time.